We propose to (1) adapt the Teen-Addiction Severity Index (T-ASI) to a Self-Report instrument; (2) develop both Internet/Intranet ("Net") technology and automated telephone survey technology (IVR) to administer the T-ASI; and (3) validate the instrument administered via IVR and Net software against the gold-standard, Clinician-Rated T-ASI in a randomized trial on 130 adolescent subjects in a residential clinical setting. We will develop and validate three new T-ASI products- (1) a Net software version of the Clinician-Rated T-ASI, (2) a Net software version of the Self-Report T-ASI, (3) an IVR version of the Self-Report T-ASI, as well as (4) normative data comparing the T-ASI with three well-known self-report instruments. Our goal is to enhance the T-ASI's clinical and research utility as well as patient acceptability while maintaining its validity. The proposed study and products should: (1) increase access to low-cost T-ASIs, (2) save labor costs by enabling patient self-assessment, (3) promote research via an inexpensive, standardized assessment instrument analogous to the adult ASI, (4) help improve clinical care for substance abuse disorders among adolescents, (5) improve addiction case management utilization review, and (6) promote outcomes tracking across the country.